This application includes subject matter related to the subject matter disclosed and claimed in copending application Ser. No. 798,978, filed Nov. 18, 1985.
This invention relates generally to apparatus and method for manufacturing plastic spiral wound hose. More particularly, this invention relates to an improved hose-making fixture and process for making spiral wound hose from overlapping and interlocking thermoplastic strips secured permanently to each other.
Plastic hoses in general are well known in the art for use in a wide variety of hose applications. In one common form, plastic hose is constructed from one or more elongated strips of a thermoplastic material wound spirally onto a mandrel with overlapping or interlocking turns. The adjacent turns are connected to each other by an appropriate bonding substance such as an adhesive material which may include some heated thermoplastic material corresponding with the elongated strip or strips. The resultant product is an elongated, lightweight, and relatively flexible plastic hose having broad utility for conveying fluids. For example, such spiral wound hoses are widely used for household vacuum cleaners, swimming pool cleaner devices, and the like.
In some applications, however, previous spiral wound hoses have not provided the desired longevity and/or capability to withstand normal operating temperatures or pressures without failure. More specifically, spiral wound hoses have been proposed for use with in-the-water swimming pool cleaners of the general type disclosed, for example, in U.S. Pat. Nos. 3,972,339 and 4,558,479. In cleaner devices of this type, the cleaner device and the hose remain in the pool water for extended time periods, with water under pressure being pumped through the hose to the cleaner device for a few hours each day thereby driving the cleaner device to perform desirable cleaning functions. However, in this environment, spiral wound hoses have experienced premature failure particularly at the adhesive interface between adjacent strip turns, resulting in substantial hose leakage and improper or failed pool cleaner operation. Such hose failures apparently have been due to the combined effects of prolonged exposure to sun and pool chemicals, and further seem to be most prevalent when water temperature is relatively warm, such as above about 85 degrees Fahrenheit. Accordingly, in the past, such pool cleaner devices have typically been provided with continuously extruded-type hoses which generally do not provide the requisite buoyancy and flexibility for optimum performance of the cleaner device.
There exists, therefore, a significant need for an improved method and related apparatus for making spiral wound plastic hose for use with swimming pool cleaner devices and in other hose applications. The present invention fulfills this need and provides further related advantages.